Automatic test equipment (ATE) plays a role in the manufacture of semiconductor devices and circuit board assemblies. Manufacturers generally use automatic test equipment, or “testers,” to verify the operation of devices during the manufacturing process. Such devices are referred to as a “device under test” (DUT) or a “unit under test” (UUT). Early detection of faults eliminates costs that would otherwise be incurred by processing defective devices, and thus reduces the overall costs of manufacturing. Manufacturers also use ATE to grade various specifications. Devices can be tested and binned according to different levels of performance in areas, such as speed. Devices can be labeled and sold according to their actual levels of performance.
Test programs have been developed for what is referred to herein as “legacy”, or pre-existing, ATE. Some test programs have been developed to account for signals that appear on inactive communication channels of the ATE. An inactive communication channel may include a communication channel in which a driver, a detector, an active load, and/or PMU have been turned off or have been otherwise made inactive. Although inactive, some communication channels can still register signal levels at ATE detectors. This may be due, e.g., to leakage current from the ATE's driver or some other unintended signals. Different types of legacy ATE typically exhibit consistent signal levels for inactive channels. Test programs have therefore been developed to expect such signals and to take these expected signals into account during testing. For such test programs, failure to register an expected signal from an inactive communication channel can result in an indication that a DUT has failed the test when, in fact, the failure indication is merely a result of an unexpected signal on an inactive communication channel.
In recent years, many types of legacy ATEs have been replaced with newer, higher-performance ATEs. Although such newer testers have many new features, many of the test programs that run on these newer testers have already been written, and depend on the performance characteristics of the legacy ATEs. For example, a test program may rely on expected bias conditions of a communication channel when its driver and active load are disabled (e.g., then the communication channel is inactive). However, a newer ATE may not necessarily have the same performance characteristics as the legacy ATE. This can affect how existing test programs are used with newer, or successor, ATE.